I have a strange problem that I am trying to solve and would appreciate input.

The problem is that some (not all) emails sent by macjordomo come to users with wrong domain. I feel that it is university's central (frontend) server messing this up but people there claim it is not possible. So I am trying to figure out at which stage the bogus domain appears.

I have turned on SMTP logging to the max and have seen that a subscription confirmation message was sent as